Delmopinol is the International Non-proprietary Name (INN) of 3-(4-propylheptyl)-4-morpholinethanol with CAS No. 79874-76-3. Delmopinol hydrochloride salt (CAS No 98092-92-3) is intended to be used in the treatment of gingivitis. The structure of delmopinol hydrochloride corresponds to the formula:

Different processes for the preparation of delmopinol and its salts are known in the art. EP 038785-A describes several preparation processes of this compound. According to EP038785-A, delmopinol can be prepared by alkylation of a 3-substituted morpholine, by dialkylation of a primary amine with a substituted bis(haloethypether or a substituted diethyleneglycol disulfonate, by reduction of a morpholone, or by transformation of the N-substituent of the morpholine into a hydroxyethyl group. EP 0426826-A describes a process for the preparation of delmopinol which comprises a cycloaddition of a morpholine nitrone to obtain a morpholine-isoxazolidine or morpholine-isoxazoline, a reductive ring opening followed by transformation of functional groups present in the side chain, and finally alkylation of the nitrogen to yield delmopinol.
Despite the teaching of this prior art, research into new preparation processes of delmopinol is still an active field since the known processes are long and require the use of harsh hydrogenation conditions, some very toxic and/or flammable reagents or solvents which make their industrial exploitation difficult and expensive. Therefore, the provision of a new preparation process of delmopinol is highly desirable.